responseFinalizer method

Future<bool> responseFinalizer(RequestContext req, ResponseContext res)

A response finalizer that saves responses to the cache.

Implementation

Future<bool> responseFinalizer(
    RequestContext req, ResponseContext res) async {
  if (res.statusCode == 304) {
    return true;
  }

  if (req.method != 'GET' && req.method != 'HEAD') {
    return true;
  }

  // Check if there is a cache entry.
  for (var pattern in patterns) {
    var reqPath = _getEffectivePath(req);

    if (pattern.allMatches(reqPath).isNotEmpty) {
      var now = DateTime.now().toUtc();

      // Invalidate the response, if need be.
      if (_cache.containsKey(reqPath)) {
        // If there is no timeout, don't invalidate.
        //if (timeout == null) return true;

        // Otherwise, don't invalidate unless the timeout has been exceeded.
        var response = _cache[reqPath];
        if (response == null ||
            now.difference(response.timestamp) < timeout) {
          return true;
        }

        // If the cache entry should be invalidated, then invalidate it.
        purge(reqPath);
      }

      // Save the response.
      var writeLock = _writeLocks.putIfAbsent(reqPath, () => Pool(1));
      await writeLock.withResource(() {
        if (res.buffer != null) {
          _cache[reqPath] = _CachedResponse(
              Map.from(res.headers), res.buffer!.toBytes(), now);
        }
      });

      _setCachedHeaders(now, req, res);
    }
  }

  return true;
}